Towards a Comprehensive Understanding of Brown Dwarf Atmospheres

褐矮星是位于恒星和行星之间的天体。虽然它们像恒星一样形成，但它们没有氢聚变，所以它们在数十亿年的时间里冷却到与行星相似的温度。通过研究褐矮星发出的红外热辐射，我们可以了解褐矮星的物理、化学及其大气。该项目涉及研究生和高中生的工作，他们将接受先进计算技术的培训，这将使他们能够创建棕矮星大气的计算机模型。这些结果将与大型望远镜的观测结果进行比较，以确定棕矮星大气中的物理性质。提案小组将对棕矮星模型大气的相空间进行重大扩展。他们将研究金属丰度、非太阳碳氧比、变化的云层厚度、云层覆盖分数、表面重力和其他因素在形成棕矮星光谱中的作用。这种辐射对流“正演模型”的广泛网格将绘制出棕矮星大气化学和物理的相空间。我们将第一次定量地了解光谱观测和模式不匹配背后的原因。大部分的科学研究将由一名研究生和每年夏天将接受指导的高中实习生共同完成。

Brown dwarfs are objects that sit at the boundary between stars and planets. Although they form like stars, they do not have hydrogen fusion, so they cool over billions of years down to temperatures similar to those of planets. By studying the the infrared heat radiation given off by brown dwarfs, we can understand the physics and chemistry and their atmospheres. This project involves the work of graduate students and high school students, who will receive training in advanced computational techniques, which will allow them to create computer models of brown dwarf atmospheres. These results will be compared to observations made from large telescopes in order to determine the physical properties within brown dwarf atmospheres. The proposal team will carry out a significant expansion of the phase space of brown dwarf model atmospheres. They will investigate the role of metallicity, non-solar carbon-to-oxygen ratios, varied cloud thickness, cloud coverage fraction, surface gravity, and other factors in shaping brown dwarf spectra. This extensive grid of radiative-convective "forward models" will map out the phase space of brown dwarf atmospheric chemistry and physics. For the first time we will gain a quantitative understanding of the reasons behind mismatches between spectral observations and models. The bulk of the science will be performed by a graduate student, in concert with high school interns who will be mentored each summer.